Position location is a key aspect of today's wireless network technology. A variety of methods and systems exist to determine a subscriber's location with varying degrees accuracy. These systems and methods use either land-based equipment or geo-positioning satellites (GPS), or a combination of both, to receive signals for the subscriber's handset, and thus fix the position of the subscriber. In addition to GPS, other examples include Time of Arrival and Angle of Arrival (and combinations thereof) to triangulate the subscriber's handset.
Older, but still used, position location technology relies on cell or sector identity to provide the general location of the subscriber. Current cell sites are fixed in relation to ground, and therefore the location of the cell can be determined based on a cell ID provided by the subscriber's handset. The cell ID is cross-referenced with a known position database and coverage area to complete the subscriber's position location determination. While this older position location information is easy to obtain, the size of most cells/sectors is such that the subscriber's location cannot be determined with sufficient precision for many current applications.
All of these existing position location methods and systems provide a predictable position location solution provided the wireless network is on the ground and the cell sites and locations are fixed relative to ground. These methods and systems will not, however, work when the subscriber is airborne, such as in an airplane.